Potential Implications of Sea-Level Rise for Belgium

Abstract

The Belgian coastal plain and the Schelde estuary are threatened by sea-level rise. While of great economic importance with a threatened population of some 0.8 million (of a total population of 10 million), assessments of these risks are limited. This article describes the physical characteristics of the coast and undertakes a qualitative interpretation of its vulnerability. Low-lying polders are the most vulnerable to sea-level rise where a major problem is water drainage during rainy periods; their varying vulnerability to sea-level rise and increase in rain intensity is assessed, including the relationship between drainage levels and saltwater seepage. Freshwater lenses developed within the dunes are also vulnerable to sea-level rise, leading to threats to drinking water supplies from saltwater intrusion. Belgian coastal defence structures and their effectiveness are discussed. Historical sea-level rise during the past century, wave and wind data, and the evolution of erosion and accretion along the coast are interpreted. For Antwerpen, a harbour city on the river Schelde, the effects of sea-level rise are far from clear. Included here are historical data on changes in tidal amplitude during the 20th century. Future research needs should focus on the quantitative interpretation of data to understand the effect of sea-level rise on beach erosion, flood risk, and fresh and salt groundwater distribution. Furthermore, a thorough socio-economic study should be undertaken to assess the vulnerability of the Belgian coast and the Schelde estuary. ADDITIONAL INDEX WORDS: Belgian coastal plain, saltwater intrusion, gravitational and artificial water drainage, coastal defences. PHYSICAL CHARACTERISTICS OF THE BELGIAN COASTAL PLAIN Geographical Position and Economic RelevanceThe Belgian coastline is on the southern North Sea and comprises an open wave-exposed coast and the more sheltered upper reaches of the Schelde estuary. The wave-exposed coast (65-km long) has a nearly continuous dune belt that protects the hinterland. This dune barrier consists of two arcs, one stretching from Dunkerque (France) to Wenduine and a second arc from Wenduine to Breskens (The Netherlands). Its continuity is interrupted by the estuaries of the river IJzer in the west and het Zwin in the east and the harbours of Oostende, Blankenberge, and Zeebrugge. The total coastal zone population is ca. 0.4 million (i.e., ca. 4% of the Belgian population), which is concentrated in the towns of Brugge, Oostende, Blankenberge, Veurne, Nieuwpoort, and Knokke (Figure 1).During summer holidays the population increases by ca. 0.3 million resident tourists and on peak days by 0.25 million

Observed mean sea level changes around the North Sea coastline from 1800 to present

“…The implications of SLR to the North Sea coastline have been assessed in various papers on a country-wide scale, e.g. by de la Vega-Leinert and Nicholls (2008) for Great Britain, Lebbe et al (2008) for Belgium, Van Koningsveld et al (2008) for the Netherlands, Sterr (2008) for Germany, Fenger et al (2008) for Denmark, Aunan and Romstad (2008) for Norway and Paskoff (2004) for France. Long-term management plans including an allowance for future sea-level rise are being formulated in the region from the scale of critical coastal infrastructure (Wilby et al, 2011) to specific regions (e.g.…”

Coastal use accelerated the regional sea-level rise

“…In Europe, many analytical and numerical models have been applied to estuary areas, e.g. the Ems, Schelde, Elbe and Seine estuaries, to estimate tidal range, storm surges and mixing and dispersion processes and evaluate the effects of coastal use (Frouin et al, 2007;Lebbe et al, 2008;Ducrotoy, 2010;Tessier et al, 2012). The Ems, for example, is a relatively well studied estuary and the relative research projects are focusing on tidal dynamics and affects of dredging in the high turbidity zone (Talke and Swart, 2006).…”

An AHP-derived method for mapping the physical vulnerability of coastal areas at regional scales

“…Beyond qualitative assessments of coastal vulnerability (e.g. Paskoff, 2004;Lebbe et al, 2008;Alpar, 2009), the challenge in mapping coastal vulnerability is to combine all of this heterogeneous information into one single map in a structured way, and to appropriately integrate the opinion of experts when data are insufficient to directly solve the problem (e.g. Fairbanks and Jakeways, 2006;Vinchon et al, 2009;Hanson et al, 2010).…”